Process of mining sulphur



mb. il W. mam MMX-@pim PROCESS OF MINING SULPHUH Filed Oct. 27. 1930 2sheetsheeu l PROCESS OP' MINING SULPHUR Filed Oct. 27, 1930 2Sheets-Sheet 2 Patented Feb. 23, 1932 'WARREN B. REED, OF MORGAN CITY,LOUISIANA PROCESS OF MINING SULPHUR Application med October 27, 1930.Serial No. 491,461.

My invention relates to a process embodying new and useful' improvementsin the mining of sulphur, or more particularly to the mining of thesubterranean deposits of sulhur occurring in the caprock of salt domes ymeans of what is generally known as the Frasch process, which inessence, consists of injecting hot Water into the sulphur-bearing zoneof the caprock portion of the salt dome, which Water being at atemperature above the melting point of sulphur, melts the sulphur whichin turn is raised to the surface by means of compressed air.

There are many hypotheses regarding the origin of the native sulphurfound in the caprock formation of certain sulphur domes.

Much research into the origin of the reactions and the chemicalcombinations Within the sulphur-bearing areas of the caprock, has notdefinitely determined the source of the sulphur or its method ofdeposition. It is conceded by many students of the subject, however,that the anhydrite mass, calcium sulphate, is the probable immediatesource of the free sulphur.

In general, it may be stated, that the original caprock before miningoperations, consistsmainly of calcite, gypsum, anhydrite, celestite andstrontionite, pyrite, hydrogen sul hide, brine, methane gas and otherhydro- Cal ODS.

After the ordinary mining process has been in operation, the bleedwaters the excess Waters drawn from the mining operations) show that theoriginal brines plus the heated waters injected for the purpose ofmining, give a resultant which carries in solution varying quantities ofcalcium sulphate, calcium bicarbonate, calcium chloride, magnesiumchloride, sodium chloride, small amounts of silica, ironi andaluminum'oxide and hydrogen sulhi e.

P It is evident, therefore, that the waters preheated above the meltingpoint of sulphur injected into the caprock, perform the function of notonly melting the sulphur, but also of dissolving the calcium carbonatesand sulphates, as well as smaller proportions of other minerals.

In the process of mining of sulphur by means of injecting water abovethe fusing point of sulphur, the sulphur lying in fissures or veins thatcan be reached freely by the hot circulating Waters, is the firstsulphur to be melted and made available, and as the porosity ofthe rockpermits the further infiltration of hot waters, other particles of freesulphur are reached and enabled to flow to points of accumulation.

It is very evident, however, from the examination ofthe specimens ofcaprock containing sulphur, that much sulphur is so sealed that itcannot be reached by circulating Waters Without the necessity of therock in which it is imprisoned being dissolved.

Unquestionably a great deal ofthe sulphur contained in the caprock areais not available until such time as solution takes place.

`The most potent available solvent of lime, is hot carbonated Waters,and my invention consists primarily of a process improving the l'presentmining of sulphur by the use of Vcaronated Waters in the place ofnatural Waters not so artificially treated. The object of this processis two-fold:

First :v To inject, into the area being mined, carbon dioxide insuperabundance for the purpose of furnishing a solvent for the calciumrocks, and an excess of carbon and oxygen for such chemical reactions asmay come about.

Second: To utilize the carbon dioxide with or without its heat contentfrom the gases of combustion of the boiler plant.

The object of my invention can be carried out either: l v

1. By forcing carbon dioxide under pressure through a well or Wellsdrilled into the zone being mined, and discharging the carbon dioxidedirectly into the area Where it will be a reagent either as gas, orabsorbed in the Waters of the mining operations, or both.

2. To combine the carbon dioxide from the combustion gases of theboilers used in the roduction of steam, for the lpurpose of heatlng theWaters of injection, y means of bypassing all or a portion of the gasesof combustion from the boilers before they enter the stack or chimney,`and forcing them under proper heat and pressure into the water that isbeing heated for pumping into the wells for the purpose of melting thesulphur.

It is evident that the gases of combustion containing carbon dioxide maybe scrubbed or purified before use, and that they may be injecteddirectly into the zone of mining operations or the water tov be used atreduced temperature or increased temperature, and that the carbondioxide so obtained may be inj ected into the water to be used before orafter the heating thereof by steam or simultaneously with the injectionof steam.

It is also apparent that the use of reservoirs to contain the gas; theuse of compressors to compress the gas; the design of the apparatus forcommingling of carbon dioxide with the waters before or after heatingmay be of manifold design and utility, but the detail of arrangement,the design of apparatus for carrying out the objectof my inventlon, doesnot in any way restrict the invention pre# cisely thereto, but what Iwish to-cover by this invention is:

1st. The process of injection of carbon dioxide into the heated watersof the sulphur bearing zone, whether the gas be injected directly intothe sulphur zone itself, or whether the carbon dioxide be injected intothe heated waters to beused for melting the sulphur before these watersare injected into the'sulphur zone.

2nd. The use of the heated dioxide taken from the gases of combustion ofthe boilers of the steam plant used in connection with the miningoperations, which use embodies the conservation of the heat of thesegases of combustion, as well as'the carbon dioxide content.

3rd. The use of carbon dioxide without I limitation as to quantity orpercentage of carbon dioxide to the amountof water used4 in the miningoperations.

In order to show diagrammatically a theoretical arrangement of thisprocess, Fig. 1 illustrates the process of injecting hot carbon dioxidedirectly into the sulphur-bearing zone being mined, through a welldrilled andl utilized for that purpose.

Fig. 2 illustrates a possible means of injecting heated carbon dioxideinto the water to be used for mining operations by means of a heaterinto which water, steam and carbon dioxide are injected, and from whichthe hot carbonated water isA removed by pump and forced into thesulphurV zone by means of a well drilled and designed for that purpose,such as used in the present methods of lmining for sulphur.

Referrin to the Fig. 1 embodiment the numeral 1 indicates a boiler witha stack 2 and damper 3 with a by-pass to blower 4, which dlscharges avariable portion of the gases of combustion into reservoir 5, fromwhence they are taken into gas compressor 6 and dlscharged atpredetermined pressure through pipe line 7 to well 8, and thenceinthrough well 8 mingle with and are absorbed r and otherwise chemicallyreact within a variable range in the zone of operations.

Well 13 is illustrative of the present-meth.-

`od of injecting hot water into the sulphur zone to be mined. Such awell is equipped with concentric pipes with hot Water intake at 14,compressed air intake at 15, and liquid sulphur discharge pipe at 16,being diagrammatic illustration of the present system in use.

lVhen this installation is operated it is to beunderstood that thesulphur mining operation will be performed by means of the wellsequipped as shown in 13 to 16, inclusive, and the sulphur will beremoved from the well in a molten state and discharged intoa bin ortankvnot shown. Duringthe operation of the well 'I contemplate `forcinginto the sulphur bearing strata, and at a point adjacent the sulphurmine, a quantity of 'carbon dioxide. This element may preferably be'obtained, as shown, from the stack of the furnace by means of which thewater is heated for the sulphur mine. It will beforced into the mineunder ressure and will be delivered laterally into t e sulphur stratumwhere it will come in contact with sulphur compounds present `therein.The CO2 will increase'the amount v of sulphur which will be melted underthe heat of the liquid in the well and will thereafter flow down to thelower part of the mine where it will be withdrawn through the sulphurwell.

In the apparatus shown in Fig. 2 the carbon dioxide vis shown as beingintroduced into the sulphur mine through the hot water inlet pipe 26thereby dispensing with the use stratum. In this embodiment. the heater,

which is ordinarily employed in heating the water delivered 1nto thesulphur mine is shown diagrammatically at 17.

This heater is shown as comprising a container, the upper end of whichis formed into a chamber 18 with inclined bafiles therein over which thewater is introduced through the pipe 19. Steam under pressure isintroduced mto the container through a steam pipeV 20 having aperforated nozzle 21 within the container. Adjacent the steam pipe 20 isthe pipe 22, through which the carbon dioxide gas is introduced into theheater. It is to be understood that this carbon dioxide may be obtainedfrom the products of combustion in the furnace or may be a commercialgas introduced under pressure into the heater where it is forced throughthe water and steam in the heater and passes with the superheated waterthrough the pump 23 into the pipe 6A with the heating element whichmelts the i sulphur and will come in contact with the sulphur and othercompounds in the well.

It is to be understood that in the diagrams shown the calcite caprock isindicated by the numeral 9. The sulphur-bearing zone l() is shown asimmediately under the caprock and the anhydrite mass l1 is below thesulphur, said anhyd'rite resting upon 'the salt stratum l2. This is, ofcourse, only illustrative as the formations differ in each individualsulphur mine.

By the use of my invention it is possible to ultimately increase to agreat extent the amount of free sulphur produced in a par- 'ticularlocality. The sulphur combined with other elements closely adjacent themain sulphur zone may be released for removal Jfrom` the well. Where thecarbon dioxide is obtained directly from the furnace there'will be nolarge element of expense in the use of the carbon dioxide and thecombination of the hot gases with the water assists in heating 'the sameand therefore furnish a further ele-V 'Inent of economy in theproduction of sulphur.

What I claim as new is: 1. In mining sulphur by injecting hotl waterinto the subterranean sulphur stratum to melt the sulphur andwithdrawing the melted sulphur, the improvement consisting of forcingcarbon dioxide into the mine to act upon mineral constituents presenttherein and free some of the sulphur', and withdrawing said sulphur.

2. fIn mining subterranean sulphur by the Frasch method, the improvementcomprising forcing hot carbon dioxide into the mine to 'free some of thesulphur in said 'mine and then removing the free sulphur.

3. In mining sulphur by the Frasch process the improvement comprisingbringing hot carbon dioxide into Contact with the water forced into themine, carrying said carbon dioxide in solution into the mine, actingupon the compounds present with said carbon dioxide and withdrawing thefree sulphur.

4L In mining sulphur by the Frasch process, the improvement includingcharging the hot water employed in mining with carbon dioxide bybringing the gases of combustion from the furnace stack into contactwith the said water and then forcing said water into contact with thecompounds in the well and then removing the free sulphur.

In testimony whereof I hereunto atlix my signature this 17th day ofOctober, A. D.

- WARREN B. REED.

